§ 1.3.2. Classification Design Criteria

The following includes specific design criteria for each street classification noted in Section 1.2.2 as required to attain adequate levels of service and safety. Table 1-7 summarizes the general design criteria for each of the street classification noted in Section 1.2.2.

• Above-minimum design values should be used whenever feasible, to assure maximum safety and operational characteristics of a transportation system. Minimum values should be recognized and used when constraints encountered are present in such quantities to justify use of minimum values.

• ADTs indicated in this document reflect typical ranges pertaining to the street classification. These ranges are not intended to be used as a sole basis for determining the street classifications. Rather, streets should be classified in regard to their functional characteristics.

• Various roadway cross-sections may be used to meet specific needs or goals; cross sections shall not be the sole basis for determining street classifications.

• Minimum centerline radii shown in the tables are based on a normal crown section.

• Design speed is an important function of roadway design. The proper design speed selection is influenced by the character of terrain, the density and type of adjacent land use, the classification and function of the roadway, the traffic volumes expected to use the roadway and by economic and environmental considerations. For example, the design of a roadway in level terrain is often based on a higher design speed than one in mountainous terrain; for one in a rural area, a higher design speed than one in an urban area; and for a high-volume highway, a higher design speed than one carrying low traffic volumes. It is important to recognize and treat individual roadways based on their specific characteristics. The design speed should be determined based on the design engineer's judgments on what design criteria are the most feasible for that particular roadway within the ranges provided in this document.

A.

Local Streets.

Local streets are intended primarily to serve traffic within a neighborhood or within a limited district. Local streets are not continuous through several districts. A design speed of less than 30 mph may be allowed for local streets if supported by an engineering study satisfactory to the entity that will adopt speed limits for the road.

1.

Local Street, General. In a residential neighborhood, a local street typically serves less than 50 SF-1 or SF-2 zoned dwelling units in number. Local streets should be designed to minimize through traffic movement; on-street parking is usually permitted (see Figure 1-22 contained in Appendix H of this manual for design criteria).

• Where SF-3 through SF-6 development exists, local streets characteristically have significant on-street parking. The criteria noted in Figure 1-23 in Appendix H of this manual is designed to address this condition.

• When applicant can demonstrate that significant on-street parking will not occur or that off-street parking comparable to SF-2 is provided, design criteria for SF-1/SF-2 may be utilized.

2.

Local Streets, Loop.

Loop streets serve low density areas. As with regular local streets, they are not intended to carry through traffic movement since the loop originates and terminates on the same street (see Figure 1-24 in Appendix H of this manual for design criteria).

3.

Local Streets, Elbow.

Elbow streets serve low density areas. They should only be designed to connect two (2) local streets or a residential collector with a local street and are not intended to carry through traffic (see Figure 1-25 in Appendix H of this manual for design criteria).

B.

Collector Street.

These streets collect traffic from other streets, serving as the most direct route to an arterial or other collector street. The five (5) types of collector streets are residential, neighborhood, commercial, industrial and primary.

1.

Collector, Residential.

A residential collector street generally serves to collect traffic from local streets within a residential district and is not intended to continue through several districts. Residential collector streets provide access to abutting property with SF-1 through SF-6 zoning, low density multifamily MF-1 zoning and neighborhood office NO zoning and generally provide on-street parking. Such streets typically exist within a subdivision adjacent to single family and to multifamily developments (see Figure 1-27 in Appendix H of this manual for design criteria).

2.

Collector, Neighborhood.

A neighborhood collector street is characterized by serving several districts or subdivisions. Neighborhood collector streets provide limited access to abutting property and may provide on-street parking, except where bus routes can be expected. Typically multifamily developments, schools, local retail developments and public facilities are located adjacent to neighborhood collectors. Direct driveway access for detached houses should be discouraged (see Figure 1-28 in Appendix H of this manual for design criteria).

3.

Collector, Commercial.

This type of a collector street serves as principal access to commercial developments. Large vehicles such as delivery trucks can be expected to utilize this type of collector. Driveways should be limited and designed to accommodate higher traffic volumes. On-street parking is generally limited or restricted. Multifamily developments may front on these collectors provided adequate off-street parking is available (see Figure 1-29 in Appendix H of this manual for design criteria).

4.

Collector, Industrial.

This type of a collector street serves as principal access to industrial developments. Vehicles served by these streets may be large, i.e., WB-50 design vehicles, requiring greater area for circulation and movement than automobiles. Driveway access should be limited and designed to accommodate higher traffic volumes and/or larger vehicles. On-street parking is generally restricted. Multifamily developments may front on these collectors provided adequate off-street parking is available (see Figure 1-30 in Appendix H of this manual for design criteria).

5.

Collector, Primary.

A primary collector street serves several subdivisions providing access from local or residential/neighborhood collectors to arterials. Primary collector streets may also be utilized to serve high traffic generating developments as determined essential through the development review process, i.e., T.I.A. Parking is restricted and access to abutting properties should be very limited (see Figures 1-31 through 1-34 in Appendix H of this manual for primary collector street design criteria).

NOTE: See Section 7 for additional information pertaining to bicycle design criteria. The street cross-sections noted in this section may need to be increased to account for bicycle routes.

C.

Arterial Street.

1.

General.

Arterial streets represent the primary network of streets for the through movement of traffic in an urbanized area. Arterial streets generally move high volumes of traffic (ADTs ranging from 5,000 to 70,000 vehicles) for great distances and at relatively high speeds. The Austin Metropolitan Area Transportation Plan identifies the streets that compose the arterial street network. Access to abutting property should therefore be limited or restricted, with on-street parking strictly prohibited. Single-family residential development should not normally front on arterial streets. In all instances, the minimum travel lane shall be 12 feet as a large variety of vehicles can be expected to utilize the system. Arterials are typically spaced every one (1) to two (2) miles within the network system. The design criteria for the various arterial streets are provided in Figures 1-35 through 1-39 contained in Appendix H of this manual.

NOTE:

• See Section 7 for additional information pertaining to bicycle design criteria. The street cross-sections noted in this section may need to be increased.

• As a means of assuring proper placement of utilities, the City may require easement dedications from the applicant.

• The Director of the Transportation, Planning and Sustainability Department should be consulted for design criteria and applicability of one way arterials.

2.

Scenic Arterial - FUTURE ADDITION

D.

Parkway.

The City of Austin defines the term "parkway" for use in the Austin Metropolitan Area Transportation Plan as a subcategory of freeway; a parkway is a roadway which has fully controlled access, no at-grade crossings and no continuous frontage roads; requires the acquisition or donation of access rights; has a generous greenspace buffer between the roadway and adjacent development and which preserves and enhances the natural landscape as much as possible.

E.

Cul-de-sac.

Cul-de-sac streets are open at one (1) end, the closed end constructed so as to facilitate traffic circulation in the reverse direction. Single outlet streets serve a network of streets with one (1) point of access (see Figure 1-58 in Appendix H of this manual). Note that the distance from the System Origination Point (SOP) to the System Termination Point (STP) should be less than 700 feet. Greater lengths, up to 3,000 feet, may be considered if there are severe environmental constraints and a second outlet is not available. Lengths exceeding 2,000 feet, however, will require approval by the Planning Commission (see Table 1-11 for Single Outlet Street Criteria).

The use of islands with cul-de-sac bubbles is not recommended. However, islands are permitted provided that the bubble has a radius of 60 feet to FOC and the island is designed with a 30 foot radius measured to FOC. When islands are proposed, a maintenance agreement must be established between the applicant and the City.

1.

Cul-de-sac, Local.

Local cul-de-sacs are intended to serve residential dwelling units. Throat width and curb basis shall meet the same design criteria as required for a general local street (see Figure 1-40 in Appendix H of this manual for design criteria).

2.

Cul-de-sac, Commercial.

Cul-de-sacs serving primarily commercial use shall have a throat designed to commercial collector criteria. Islands should be discouraged and are not permitted without the approval of the Director of the Transportation, Planning and Sustainability Department (see Figure 1-41 in Appendix H of this manual for design criteria).

3.

Cul-de-sac, Industrial.

The vehicles serviced by this type of cul-de-sac are often large, therefore, islands will not be permitted without the approval of the Director of the Transportation, Planning and Sustainability Department. The throat shall be designed to industrial collector standards (see Figure 1-42 in Appendix H of this manual for design criteria).

Dead-end streets that are stubbed out for future extension to the adjacent property must terminate in an open-ended cul-de-sac (as illustrated in Figure 1-42a in Appendix H of this manual), unless the dead-end street is less than 150 feet long, in which case the cul-de-sac bubble may be omitted. If the stubbed-out street is not extended when the adjacent property is developed, a bubble is required on the adjacent property, or access to the dead-end street from the adjacent property must be prohibited.

F.

Single Outlet Streets.

Traffic issues pertaining to single outlet streets are partially mitigated by: (1) providing mid-block turnarounds (or cross-streets/loop streets), (2) increased pavement widths and (3) utilization of divided roadways, as noted in Table 1-6.

The criteria pertaining to single outlet streets are applicable to new developments whether the single outlet is temporary or permanent. When future extensions to the street system are anticipated, which will provide additional outlets, a temporary restriction may be placed on the amount of development allowed, until an additional outlet becomes available.

TABLE 1-6 SINGLE OUTLET STREETS**
ADT	Street Width (FOC - FOC)
Less than 300	30′
300 - 1000	36′
1000 - 2500	40′ or 44′
2500 - 4000	2 @ 24″ w/16′ min. median width
Greater than 4000	TIA Required
** If the distance from the SOP to the STP exceeds 2000′, then the single outlet street must be designed with 2 @ 24 w/16′ minimum median width.
Source: City of Austin, Department of Public Works and Transportation

 

G.

Alley.

An alley is a passageway designed primarily to provide access to property. The existing/planned street network in the immediate vicinity should impact the decision for planning one (1) or two (2) way alleys. Typically, a one (1) way alley should not be encouraged unless the alley is short. Parking in alleys should be restricted.

1.

Alley, One (1) Way.

Where applicable, the direction of travel on a one (1) way alley should be consistent with the surrounding street network (see Figure 1-43 in Appendix H of this manual).

2.

Alley, Two (2) Way.

In an effort to reduce the potential for motorist confusion, the combining of two (2) and one (1) way alleys in the same subdivision should be avoided (see Figure 1-44 contained in Appendix H of this manual).

Table 1-7 Geometric Design Criteria Summary Table
Functional Classification	TCM Figure	ROW	Paving Width LOG-LOG	Median Width FOC-FOC	Curb Basis	Design Speed (mph)	Typ Length of Street	Typ Spacing of Cross Street	Min Centerline Radius	Side walk
Local
SF-1 to SF-2 Zoning	1-22	50	27	-	10	25, 30	<1500	300	180,300	4
SF-3 to SF-6 Zoning	1-23	56	33	-	10	25, 30	<1500	300	180,300	4
Collectors
Residential	1-27	60	37	-	10	30, 35	<1 mi	300	300,470	4
Neighborhood	1-28	64	41	-	10	35	1-2 mi	500	470	4
Commercial	1-29	70	45	-	11	35	<2 mi	500	470	6
Industrial	1-30	90	57	-	15	35	<2 mi	500	470	5
Primary	1-31 to 1-34	var	var	var	var	var	> 1mi	1000	var	5
Arterials****
MNR 2 WC	1-34A	60	30	-	13.5	45	>1 mi	1000	1000	5
MNR 2 BL	1-34B	64	34	-	12.5	45	>1 mi	1000	1000	5
MNR 4 WC	1-35A	82	54	-	12.5	45	>1 mi	1000	1000	5
MNR 4 BL	1-35B	86	58	-	12.5	45	>1 mi	1000	1000	5
MAU 4 WC	1-36A	82	54	-	12.5	45	>1 mi	1000	1000	5
MAU 4 BL	1-36B	86	58	-	12.5	45	>1 mi	1000	1000	5
MAD 2 WC	1-37A	70	42	-	12.5	45	>1 mi	1000	1000	6
MAD 2 BL	1-37B	74	46	-	12.5	45	>1 mi	1000	1000	6
MAD 4 MEDIAN + WC	1-37C	110	2 @27	20	15	45	>1 mi	1000	1000	6
MAD 4 MEDIAN + BL	1-37D	114	2 @27	20	15	45	>1 mi	1000	1000	6
MAD 4 TWLTL*****	1-37E	100	66	-	15.5	50	>1 mi	1000	1000	6
MAD 6	1-38	140	2 @41	23	14.5	50	>2 mi	1300	1400	6

 

Functional Classification	Min Tang Length sep. curves	Max Sust'nd Grade (%)	Max Grade <500′ (%)	Min Horiz Tang Length Approaching			Min Spacing between Median Opening	Des Min Landing w/Grade <2% Approacing			Min Driveway Spacing*, ***
				Loc	Col	Art		Loc	Col	Art	T1	T2
												O	U	D
Local
SF-1 to SF-2 Zoning	50	15	15	50	50	50	-	50	50	50	**	50	50	-
SF-3 to SF-6 Zoning	50	15	15	50	50	50	-	50	50	50	10	50	50	-
Collectors
Residential	100	10	12	50	50	50	-	80	80	100	25	50	50	75
Neighborhood	100	10	11	50	50	50	-	80	80	125	25	50	50	75
Commercial	100	10	11	50	75	75	-	80	80	125	-	50	75	75
Industrial	100	8	8	50	75	75	-	80	80	125	-	50	75	75
Primary	100	9	11	50	75	75	var	80	100	125	-	50	100	100
Arterials****
MNR 2	150	7	7	-	75	75	-	-	125	125	-	75	150	-
MNR 4	150	7	7	-	75	75	-	-	125	125	-	75	150	-
MAU 4	150	7	7	-	75	75	-	-	125	125	-	75	200	-
MAD 2	150	7	7	-	75	75		-	125	125	-	75	-	200
MAD 4 MEDIAN	150	7	7	-	75	75	450-750	-	125	125	-	75	-	200
MAD 4 TWLTL*****	150	7	7	-	75	75	-	-	125	125	-	75	-	200
MAD 6	200	7	7	-	75	100	450-750	-	125	125	-	75	-	200
* Special ordinances apply to Principal Roadways and Hill Country Roadways (See Table 5-2)
** Limited to one driveway per property
*** T1 = Type 1, t2 = Type 2; O = One Way, U = Undivided, D = Divided
**** MNR = Minor Arterial, MAU = Major Undivided Arterial, MAD = Major Divided Arterial, WC = Wide Curb Lane, BL = Bike Lane
***** TWLTL = Two Way Left Turn Lane
Note: Selection between wide curb lane and bike lane sections should conform to the facility designation for the roadway in the Austin Bikeway Plan

 

Table 1-7A Notes:

DDZ = Desired Development Zone within Austin's 5-mile Extra-Territorial Jurisdiction

DWPZ= Drinking Water Protection Zone within Austin's 5-mile Extra-Territorial Jurisdiction

ROW = Right-of-Way Existing right-of-way (ROW) widths in COLUMN 6 denoted with an asterisk (*) were estimated by TPAS staff using ARCInfo/ARCView. All other existing ROW widths were taken from Travis County Appraisal District tax plats.

1

Indicates Council Amendment to 2024 AMATP on August 16, 2001.

2

Indicates Council Amendment to 2025 AMATP on August 23, 2001.

3

Frate Barker Rd. was deleted from the 2025 AMATP on September 27, 2001 by Ordinance No. 010927-134.

Key to Roadway Classifications

The number after the roadway classification indicates the number of lanes. A "MAD" designates a roadway divided either by a raised median, flush center left turn lane, or a central drainage ditch. The choice of one or the other is to be made in the roadway design and construction process.

FWY	Freeway
PKWY	Parkway
EXPY	Expressway
MAD	Major Arterial Divided
MAU	Major Arterial Undivided
MNR	Minor Arterial
MIS	Major Investment Study- the recommended cross section is subject to the results of a major investment study
—-	Under the Existing 1997 column 3, " —-" , indicates the existing condition of the roadway as of 1997
NHS	National Highway System-Roadway is included in the National Highway System
IH/BR IH	Interstate Highway/Business Route Interstate Highway
SH	State Highway
FM	Farm to Market Road
RM	Ranch to Market Road
CR	County Road

 

COLUMN 3 shows road segments as they existed in 1997

COLUMN 4 shows the City of Austin 2025 AMATP Plan for the road segment

COLUMN 5 indicates the maximum required ROW for the upgrade

COLUMN 6 indicates the existing ROW available along the segment

COLUMN 7 indicates the minimum amount of ROW that exists along the segment

COLUMN 8 indicates the maximum amount of ROW that exists along the segment

COLUMN 9 indicates the natural environmental sensitivity of the area through which each roadway passes

COLUMN 10 indicates with a "B" that the roadway segment is part of a Metropolitan Bike Route System

COLUMN 11 indicates that the roadway segment is part of the Austin Bicycle Plan. wc= Wide Curb; bl= Bike Lane; sh= Shoulder

COLUMN 12 shows recommendations for a particular roadway segment

COLUMN 13 indicates a roadway segment is in the Barton Springs Edwards Aquifer Recharge Zone

COLUMN 14 indicates a roadway segment is in the Barton Springs Edwards Aquifer Contributing Zone

COLUMN 15 indicates a roadway segment is in the Northern Edwards Aquifer Recharge Zone

SOURCES:

Data in COLUMNS 1, 2, 3, 9, 10, were taken from the 2025 Capital Area Metropolitan Planning Organization (CAMPO)Transportation Plan.

Data in COLUMNS 13-15 provided by COA Watershed Protection Dept. Feb. 2001.

Existing right-of-way (ROW) widths in COLUMN 6 denoted with an asterisk (*) were estimated by TPAS staff using ARCInfo. All other existing ROW widths were taken from Travis County Appraisal District tax plats.

Table 1-7A Attachment 1:
U.S. Fish and Wildlife Service
Recommendations for Protection of Water Quality of the Edwards Aquifer
September 1, 2000

These recommendations were produced with the intent of identifying measures that would achieve an objective of "non-degradation" of water quality for projects within the Edwards Aquifer. While true "non-degradation" is not technically possible today, these recommendations strive to maintain current water quality. Anyone implementing projects following these recommendations is encouraged to go beyond water quality maintenance and demonstrate ways that the project can achieve improved water quality.

These recommendations to protect water quality are current as of the date listed above and will change as new information becomes available. They are not rules, regulations, laws or requirements. These recommendations were formulated by reviewing existing scientific information, existing rules and regulations, and by working closely with water quality engineers and biologists. These recommendations pertain to the protection of water quality for Federally listed endangered and threatened species. These measures do not address other possible impacts to Federally listed endangered or threatened species.

It is recognized that strict adherence to any general set of development recommendations may be problematic at the project level. Problems that arise are usually very site-specific and should be dealt with on a case-by-case basis. Variations from these recommendations could be used and still achieve the "non-degradation" objective. In cases where flexibility is appropriate, variations should be designed to achieve the "non-degradation" objective.

1.

Buffer Zones.

Buffer zones (undisturbed natural areas) should be established for the stream drainage system and for sensitive environmental features within the Edwards Aquifer watersheds.

A.

Buffer zones should remain free of construction, development, or other alterations. The number of roadways crossing through the buffer zones should be minimized and constructed only when necessary to safely access property that cannot otherwise be accessed. Other alterations within buffer zones could include utility crossings, but only when necessary, fences, low impact parks, and open space. Low impact park development within the buffer zone should be limited to trails, picnic facilities, and similar construction that does not significantly alter the existing vegetation. Parking lots and roads are not considered low impact. Neither golf course development nor wastewater effluent irrigation should take place in the buffer zone. Stormwater from development should be dispersed into overland flow patterns before reaching the buffer zones.

B.

Each stream should have an undisturbed native vegetation buffer on each side as follows:

Streams draining 640 acres (one square mile) or greater should have a minimum buffer of 300 feet from the centerline on each side of the stream.

Streams draining less than 640 acres but 320 or more acres should have a minimum buffer of 200 feet from the centerline on each side of the stream.

Streams draining less than 320 acres but 128 or more acres should have a minimum buffer of 100 feet from the centerline on each side of the stream.

Streams or swales draining less than 128 acres but 40 or more acres should have a minimum buffer of 50 feet from the centerline on each side of the drainage.

Streams or swales draining less than 40 acres but 5 or more acres should have a minimum buffer of 25 feet from the centerline on each side of the drainage.

C.

Sensitive environmental features should have a minimum buffer of 150 feet around the feature (radius). If the drainage to a feature is greater than 150 feet in length, then the minimum buffer should be expanded to a minimum of 300 feet for the area draining into the feature. Sensitive environmental features include: caves, sinkholes, faults with solution-enlarged openings, fracture zones with solution-enlarged openings, springs, seeps, or any area that holds water or supports mesic vegetation for sustained periods. Possible sensitive features and sensitive features as defined by the "Instructions to Geologists for Geologic Assessments on the Edwards Aquifer Recharge/Transition Zones", TNRCC document 0586 (Rev. 6/1/99) should have these buffers established.

2.

Low-impact development designs.

Low-impact development design is defined not only by impervious cover, but also by a philosophy of development planning, engineering design and construction, and tenant occupation that reduces the impact upon the surrounding environment. The goal of low-impact development design is to produce a product with the least effect upon the natural biota and the hydrologic regime of the site. A source of guidance for such design may be obtained from Low-Impact Development Design Manual (hereafter LIDDM), Department of Environmental Resources, Prince George's County, Maryland, November 1997. Site specifics will affect the applicability of the measures to the Central Texas area.

Recharge zone development should be limited to no more than 15% impervious cover in the uplands zone. Contributing zone development should be limited to no more than 20% impervious cover in the uplands zone. The uplands zone includes all land not within a buffer zone and not within golf course turf areas subject to fertilizer, pesticide and herbicide applications. Buffer zones and golf course turf areas should not to be included in impervious cover calculations.

Preservation of large, undisturbed upland areas through the use of innovative site design techniques that, for example, cluster development is encouraged. Cluster development should also incorporate design principles that: reduce roadway widths; reduce residential street lengths using alternate street layouts that increase the number of homes per unit length; reduce residential street right-of-way widths; minimize the use of residential street cul-de-sacs using alternative turnaround designs; use vegetated channels instead of curb and gutters; and use subdivision designs that incorporate, where appropriate, narrower lot frontages. Additional recommendations for low impact designs include the use of non-toxic building materials, water conservation, rainwater harvesting, wastewater recycling, and xeriscaping.

3.

Provisions for increased development intensity.

Onsite development intensity may be increased if additional land, conservation easement, or development rights are acquired offsite. Offsite land should be located in the same watershed and aquifer zone as the development. Offsite land being used to offset higher development on a project should not include areas that would be part of a buffer system under these recommendations.

In the recharge zone, development should not exceed a maximum of 30% on-site impervious cover of the upland zone (developed site) when sufficient offsite land is provided. Such offsite land should be maintained in an undeveloped condition (25 acre tracts or larger) in perpetuity such that the effective impervious cover (developed land plus offsite land) does not exceed 10% impervious cover. In the contributing zone, development should not exceed 35% on-site impervious cover of the upland zone when sufficient offsite land is provided. Such offsite land should be maintained in an undeveloped condition in perpetuity such that the effective impervious cover of the combined tracts does not exceed 15%. Golf course areas receiving fertilizer, pesticide, and herbicide applications should be excluded from the uplands area calculation and should not be use to calculate allowable impervious cover. The offsite acreage may be reduced when more sensitive land can be preserved; however, this consideration should be made on a case-by-case basis.

Offsite land should be in a low impervious cover condition (2 percent or less) in perpetuity. Conservation easements or deed restrictions should be used to ensure permanent protection. Offsite lands should also have provisions made for appropriate long term management, which could include a property owner, home-owners association, river authority, municipality, county or land trust. Offsite land should be in large contiguous areas and used to augment existing conservation efforts, to the greatest extent practical.

4.

Stormwater quality treatment.

The stormwater management goal should be to prevent degradation of the aquifer and surface water by meeting specific non-degradation performance objectives. Satisfying the non-degradation goal should be demonstrated by meeting the following two objectives:

The development should not result in an increase in annual average stormwater pollutant loads over pre-development conditions for discharges from the site.

The development should preserve the current form and function of the drainage network/stream system. This may be achieved by either non-structural or structural means, depending upon the nature of the development.

The use of vegetative practices is encouraged to meet the goals of non-degradation and erosion control. Key to the success of vegetative practices is providing a low impact development design incorporating elements that more closely mimic the existing hydrologic setting. Developments or portions of developments at 10% impervious cover or lower should be able to achieve such designs. Non-structural approaches are encouraged whenever feasible in order to avoid concentrating runoff patterns. Relying primarily on vegetative and other non-structural approaches increases the likelihood of long-term water quality protection as well as minimizing future maintenance responsibilities. Developments or portions of a development with impervious cover greater than 10% are encouraged to rely on such practices to achieve non-degradation, though it is understood that permanent, structural best management practices should be employed in many instances. When non-structural controls are used to achieve non-degradation, then it should be demonstrated for streambank erosion that the pre-development levels of stream flow are maintained for streams draining at least 40 acres. If the site to be developed lies within a contributing area of less than 40 acres, or if there is no defined channel at the outlet, then pre-development levels of flow should be maintained for the point(s) of the greatest drainage area within the development. When structural controls are used, capturing the runoff from the 1-year, 3-hour storm event, and releasing it over a 24-hour or greater period should accomplish stream channel erosion protection.

5.

Construction-related erosion and sedimentation controls.

Development should incorporate an erosion control plan in accordance with the temporary best management practices of the Nonpoint Source Pollution Control Technical Manual and/or the Technical Guidance Manual on Best Management Practices (June 1999, TNRCC, RG-348). Temporary erosion and sedimentation control plans should also be applied to individual lots as they are developed through appropriate mechanisms.

6.

Maintenance plans.

Plans for maintenance of structural water quality and erosion controls should be prepared and implemented in accordance with the Nonpoint Source Pollution Control Technical Manual and/or the Technical Guidance Manual on Best Management Practices (June 1999, TNRCC, RG-348). Documentation should be provided that ensures that sufficient annual funding exists to properly maintain stormwater treatment facilities.

7.

Environmental education.

An educational program should be implemented to inform the public about the sensitivity of the aquifer and their potential impacts on water quality. The developer or owner of the project should include within the development plans an environmental educational program for residential, industrial, and/or commercial developments. Topics may include information about endangered aquatic species, karst geology, best management practices, buffer zone maintenance, fertilizer application, pesticide use, organic gardening, and disposal of hazardous household chemicals. Materials used should be obtained from the Fish and Wildlife Service, TNRCC, American Water Works Association, National Ground Water Association, Water Environment Federation, or from another appropriate sources. Development of kiosks, displays, video, and/or other media to present material covering a variety of non-point source pollution control topics should be encouraged. Alternative educational efforts, such as site-specific recharge feature displays and educational nature trails should also be encouraged. Similarly, all developments should include an integrated pest management plan to minimize exposure of stormwater runoff to chemicals (fertilizers, herbicides and pesticides).

Table 1-7A Attachment 2:
Additional Criteria for Construction of Roadways in the Drinking Water Protection Zone

The Austin City Council has established criteria about the expenditure of bonds should they be approved:

Unless the road is authorized by an election of the City of Austin or another jurisdiction and the spending is approved by the Austin City Council, the bond proceeds will not be used to fund matches for road infrastructure of right-of-way through:

□  The Drinking Water Protection Zone.

□  A City of Austin preserve.

□  A City of Austin destination park

For each proposed use of bond proceeds for a road project, City staff must make a recommendation on the proposed use through an analysis of:

□  The tax equity and social equity implications for City of Austin residents.

□  Impact of the proposed project on the Drinking Water Protection Zone.

□  Impact of the proposed project on increased mobility, decreased congestion and air quality.

□  Any alternatives to the proposed project that provide the same or better congestion relief with improved air quality